Refractory brick for use in suspended furnace roofs



Aug. 8, 1950 HEUER a 2,517,876

- REFRACTORY BRICK FOR USE IN SUSPENDED FURNACE ROOFS 2 Sheets-Sheet '1Filed July 3,: 1944 Patented Aug. 8, 1950 REFRACTORY BRICK FOR USE INSUSPENDED FURNACE ROOFS Russell Pearce Heuer, Villa Nova, l'a., assignorto General Refractories Company, a corporation of PennsylvaniaApplication July 8, 1944, Serial No. 543,241

4 Claims. (Cl. 11099) similar mechanically supported structures whichcomprises a metallic socket co-molded with the brick and forming anintegral part thereof.

Another purpose is to provide a refractory ma- I terial which whenco-molded with a metallic hanger means in the form of a socket issuitable for furnace use without high temperature kiln firing. g

A further purpose is to provide a co-molded metallic socket located atthe cool end of the brick in such a manner as to obtain a maximumeffective distance between the socket and the heated end of the brick.

A further purpose is to support a brick from a bracket or socket whichis molded into the brick and may thus be set at any point selectedwithin the end of the brick, and which sharply defines the character ofengagement between the brick and its supporting means or hanger.

A further purpose is to secure well defined and exact contact between abrick and its hanger support, restricting that contact to the surfac ofan inserted socket.

Further purposes appear in the specifications and in the claims.

I have preferred to show but two forms of socket, selecting forms whichare practical and reliable, but which have been selected by reason of,their excellence in illustrating the invention. Figure l isa'perspective of one form of socket. Figure 2 is a fragmentaryperspective of one end of a brick containing the socket of Figure 1.Figures 3 and 4 are side elevations of a mold used in explaining themolding operation.

Figure 4 is a side elevation of another form of mold than that in Figure4.

Figures 5 and 6 are fragmentary views at right angles to each othershowing the socket of Figcally supported parts of high temperaturefurnaces is widely practiced. There are many wellknown advantages tosuch construction. Diverse means of suspension and support have beenproposed.

Generally a metallic hanger is provided and the refractory brick are soshaped and arranged as to be engaged by the hanger at a substantialdistance from the extreme end of the brick so that enough refractory isengaged by the hanger to give the proper strength for support. By sodoing, the efficiency of utilizing the refractory which lies between thehanger and the extreme end of the brick is largely wasted In the courseof the furnace operation the refractory material at the hot face of thebrick wears away. As the brick gets thinner 'the temperature of themetallic hanger rises and at some point-exceeds its safe workingtemperature. It is then customary to replace the worn-out brick with newbrick. This involves both the cost of the brick and the labor cost ofreplacement.

In cases where the refractory comprises relatively cheap substances suchas flreclay, the efflciency of utilization of the refractory brick hasnot been so important. More recently, however, refractory substancescomprising chrome ore and/or magnesia, described as non-acidrefractories, as set forth in my U. 3. Patents 2,154,813 and-2,l55,165,have been used in suspended roofs. These materials are more expensiveand the efficiency of their utilization is important.

I have found that it is possible to improve the efliciency ofutilization of the refractory in suspended roofs and similarmechanically supported parts of furnaces, saving not only in brick butalso in labor for replacement. To do this I provide a socket which islocated nearer to the cool end of the brick than is the part of thebrick otherwise engaged by the hanger, thereby obtaining a maximumeifective thickness of refractory between the hanger and the heated endof the brick.

My preferred form of hanger-engaged insert within the brick comprises ametallic socket I as shown in Figure l. The metal may be rolled steel ormalleable cast iron (these are commonly described as ferrous metals),heat resistant alloy or "other desired material. I co-mold this metallicinsert with the refractory material 3 under pressure to form therefractory brick 9'. A section of such a brick, showing the co-moldedsocket in it, is shown in Figure 2. By co-molding I imbed at least 'apart of the hanger socket in the refractory and thus provide a definitepoint of support which is located near to, at or even outside of thecool end of the brick. A second form of insert ll having contact outsideof its brickis seen at I in Figure 7. I

The insert may be U-shaped as in Figure 2, or otherwise shaped, such asthe Y in Figure 7 or a T, V, L or Her other examples. Theinsert shouldbe shaped so as to cooperate with the hanger or support used for thebrick.

The socket must sharply define theshape and position of the surface tobe engaged by an outside hanger II as well as the exact position withinthe brick at which-hanger engagement takes place. I

The two legs l2 of the U-shaped piece in Figure 1 may be provided withtabs it and/or recesses it (Figure 1) the walls of each of which, whenco-molded, engage the refractory and hold the socket firmly in place. InFigure 2 the refractory does not entirely fill the space between thelegs of the U-shap'ed socket. A void space I! is provided. Into thisspace I! the hanger or support I I may be fitted, making contact withthe under surface ii of the bend and inner side surfaces II, II.

Both the extension of the tabs laterally outwardly into the body of thebrick and the projection of the body of the brick within the recessesleft by bending them out, serve thoroughly to seat and hold the socketwithin the brick. One pair of tabs and one pair of recesses lie betweenthe space I! and the relatively "free" ends I9, of the legs, asdistinguished from the end of the socket at which the legs are united bythe transverse strap 2|.

Figures 5 and 6 show one method of assembling the bricks on the hangersto form a suspended roof. Figure 6 is a view taken at right angles tothat of Figure 5. In both figures a conventional supporting bar or rod22 is shown. Hansers ll of suitable heat-resistant metal are suspendedby hooks 23 from the bars or rods. The

T hangers are interchangeable. but as used the tions are formed asfairly snug, slightly tapered fits within the sockets. They prevent thebricks from sliding off the hangers before the bricks are put inposition in the roof, and prevent the sockets from tilting or turningunder pressure durin molding.

Two bricks may behung from each hanger. The hangers may be grouped inpairs as shown, with the hooks 23 engaging the bar from the left andfromthe right. In this waya simple roof construction is obtained. Theassembly is easy and a small number only of supports-and hangers-isrequired.

Not only can other shapes of hanger inserts co-molded with their brickbe used but other types of supporting members and various ways ofdisposing the hangers from the supporting means will serve the purpose.The insert may extend beyond the end of the brick as shown in Figure '7.The insert 0' is here engaged by the hanger at the opening 26. Thesocket I may also,

be supported by engaging it through opening 26.

The bricks can be hung singly or in pairs or groups and the hangers canbe assembled on the supporting members conventionally. In any of theforms the socket is co-moided'with the brick and preferably is providedwith means for looking itself firmly to the refractory, as for examplethe tabs and/or recesses as shown in Figure 1.

One method of co-molding the socket and the refractory to produce thebrick shown in Figure 2 is illustrated in Figures 3 and 4. In Figure 3 amold box 21 of proper dimension is indicated. This mold is closed at thebottom by a plunger 28. The top of the mold may be closed by a topplunger 20. One or both plungers is or are actuated by a hydraulic pressor suitable mechanical press. The press should be sufflcient to exert aforming pressure on the brick of at least 1500 lbs. per sq. inch. Aforming pressure of 5000 lbs. per sq. inch is more desirable and up to10,000 lbs per sq. inch or more is preferred.

The prepared refractory mix, ready for form- ,ing, is charged into themold opening. The top plunger is provided with a plug 30 of properdimension to form the opening 34 through the top at the side of thebrick and also to reach into the socket to support the socket and keepbrick mix out of the recess 32. The opening 3| gives a space by whichafter the pressing operation the plug 30 can be withdrawn from the brickand by which lateral access may be had through the side of the brick atthe end as shown in Figure 2.

The socket I is supported on this plug. It may be held in place upon theunder side of the upper plunger and at any desired di'stance below it.There is a decided advantage in having the point of support high up inthe brick or even above its surface in that the metal is thus spaced toa maximum from the furnace heat.

Since the side of the brick is uppermost in Figures 3 and 4, thedistance of the socket below the upper die in these figures representsthe distance of the socket in from the side, placing the socket in linewith the majoraxis a--b of the brick, for example, in Figures 5, 6 and'7, so as to provide a line of support through the center of gravitycoinciding with the major axis line of the brick.

On the other hand, if the sockets be placed at different distances fromthe sides or edges of the brick so that the sockets lie Outside of themajor axis of the brick as in Figures 6 and 7", the bricks are canted toan angle 0 determined by the extent that the socket lies outside of saidaxis. The angle 0 is the angle between the major axis and the line ofsupport c-d between the point of support and the center of gravity.

The socket plug may be held in place beneath the top plunger by magneticor other means. The socket and plug interfit snugly so that there islight friction between them.

In order to co-mold the socket and the refractory the top plunger ismoved down under pressure to the position shown in Figure 4. By

so doing the socket is imbedded in the refractory and i held firmly inposition. The top plunger and plug are then withdrawn, leaving theformed brick with the hanger recess in the mold. The

bottom plunger then moves upward and the brick is discharged from themold. It is important that the plug used to form the recess be taperedor shaped in such a way as to permit its withdrawal from the formedbrick without damage to the refractory.

Chrome ore, 6x28 mesh, 60% Dead-burned magnesite through 50 mesh, 40%

To this mixture is'added 2% air-floated kaolin and a, solution ofsulfuric acid suillcient to provide about 4% of moisture and 1% ofsulfuric acid in the prepared mix. Other compositions and types ofrefractory may also be used.

After molding, the refractory brick are dried at about 300 1". or othersuitable temperature. preferably under conditions of controlledhumidity; After drying, the bricks are ready for use without hightemperature kiln firing. It is necessary to avoid any high temperaturekiln treatment which would melt the hangers imbedded in the brick oroxidize the metal enough to cause it to suffer a loss in strength orutility.

tion of mechanically supported furnace walls, as,

I of the brick, including in the slot a portion of the U with the bar ofthe U extending across the for example, the end walls and front or back1 walls of open hearth furnaces. Mechanically supported walls comprisingbrick which are held .in place by forces of tension applied to theindividual bricks in the wall are better than conventional unsupportedwalls which are held in place largely by compressive forces created bythe force of gravity or the action of buck-stays, tie-rods, etc. Suchmechanically supported walls give longer life with less'spalling of thebrick, the working dimensions of the furnace are maintained with greateraccuracy during the furnace campaign and the destruction of furnacewalls by charging machines is materially lessened. The use of a brickcomprising also-molded socket or supporting means in such walls issimple and cheap and the refractory present is eillciently utilized.

It i highl desirable that the socket. within slotabove the bottomthereof, providing a hanger recess in the slot below the bar of the U,the

. refractory mass comprising non-acid refractory pressure comolded withthe insert, interlocking with the insert along the sides of the U,unfired and suitable for use in unflred condition.

y 2. Ina refractory brick, an inverted ferrous metallic U-shaped inserthaving a bar extending across the top and sides depending below thesides of the bar, and a ncnacid refractory mass in brick form pressurecomolded with the insert, having a slot at the top end face from onesidewall part only of the distance to the opposite sidewall and partonly of the distance toward the bottom of the brick, including in theslot the upper portion of the U with the bar of the U extending acrossthe slot above the bottom thereof, and the sides of the U embedded inthe refractory below the bottom of the slot, leaving a hanger recess inthe slot below the bar of the U and the insert interlocking with therefractory along the sides of the U, the brick being unfired andsuitable for use in unfired condition.

3; In a refractory brick, an inverted metallic U-shaped insert having abar extending across the top and sides depending below the ends of thebar, laterally extending wings from the sides and the brick, of whatevershape, shouldbe put in during the molding of the brick, so that thecompression of the brick may press the refrac- 'tory tightly against andabout the socket and that the refractory walls "engaging the socket mayhave the surface characteristics due to the considerable pressureexerted in molding the brick.

With the higher pressures the spaces which otherwise occur between theparticles of the brick are eliminated to a large extent by crowdingother particles into the spaces which would 1 otherwise be left, notonly giving denser brick structure but giving correspondence of the wallof refractory next to the insert much closer than could otherwise beattained. "-There is, therefore,

- not only greater density of the brick itself but greater averagedensity of the brick unit con-' sidered' as" a combined structure.

' An additional capability where the refractory is non-acid and theinsert is ferrous metal or other oxidizable metal is that oxidation ofthe metal of the insert at the high temperature of I. use will tend tomake it weld with the refractory extending laterally wider than thesides of the U, and a non-acid refractory brick mass'unfired andsuitable for use in unfired condition, pressure comolded with the insertand having a slot at the top end face from one sidewall part only of thedistance to the opposite sidewall and part only of the distance towardthe bottom of the brick, including in the slot the upper portion of theU with the bar of the U extending across the slot above the bottomthereof, leaving a hanger recess in the slot below the bar of the U, therefractory embedding the ends of the U, and embedding the wings alongthe sides of the U.

4. In a refractory brick, an inverted metallic U-shaped insert having abar extending across the top and sides depending below the ends of thebar and a mass of refractory in brick form pressure comolded with theinsert, containing principally a mixture of coarse chromite grains andfine magnesia grains with a binder, having a slot at the top end facefrom one sidewall part only of the distance to the opposite sidewall andpart only of the distance toward the bottom of the brick, including inthe slot the upper portion as of the U, with the bar of the U extendingacross the slot above the bottom thereof, leaving a and will improve(rather than impair) the flrm .contact between the insert and therefractory, since, the volume of the oxide is greater than that of theoriginal metal.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is: a 1

.1. In a refractory brick, an inverted metallic U-shaped insert having abar extending across the topand sides depending below the ends of.

the bar, and a refractory mass in brick form having a slot at the topend face from one sidewall part only of the distance to the oppositesidewall and part only of the distance toward the bottom hanger recessin the slot below the bar of the U, the insert interlocking with therefractory along the sides of theU, the brick being fired and suitablefor use in unfired condition.

' RUSSELL PEARCE HEUER.

REFERENCES CITED The following references are of record'in the file ofthis patent:

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